1. Field
This invention is generally related to wireless communications, and more particularly, to systems and methods of constructing and operating an adaptive linearity communication device for a wireless communication system.
2. Background
Wireless communication devices may include receivers that process incoming signals to extract information or data from a transmitted signal. Conventional receivers include components that have a response dependent on bias. The bias may be a voltage bias and/or a current bias depending on the particular receiver component. Typically, the linearity of operation of the receiver component increases with the bias that is applied. As the bias is reduced from an optimum linearity level, the linearity of a receiver component decreases and the response becomes increasingly non-linear.
Intermodulation distortion (IMD) increases as the response becomes non-linear. IMD degrades performance of the receiver by introducing interference energy within the receive band. When a non-linear response is applied to two or more interfering signals, the signals may mix to produce IMD products (signals). Accordingly, interfering signals processed by the receiver component with a non-linear response may result in IMD signals within the receive band, although one or more of the original interfering signals are outside the receive band. Sensitivity and overall receiver performance is reduced as IMD signals increase. Unfortunately, increasing bias and operating components in a linear mode is inefficient. Slight increases in bias and linearity may result in large additional power consumption. In wireless communication devices where power is limited, increasing bias to the receiver components may significantly reduce the battery life (“talk time”).
Various techniques have been employed to increase the linearity of receiver components while minimizing the adverse affect upon the battery life. However, the previous attempts remain inadequate to optimize the operation of receiver components while conserving battery life. Therefore, there is need for improvement.